日本樱花今年将在何时盛开？想去日本旅游的你，是不是也在琢磨根据这个时间安排行程？在如今的信息时代，樱花花期的预测也紧跟潮流，除了人员观测，大数据、算法、甚至人工智能齐上阵。只要密切关注相关的预测平台信息发布，保准错不了。

As spring approaches in Japan, the country's weather forecasters face one of their biggest missions of the year: predicting exactly when the cherry blossoms will bloom.

随着春天的临近，日本的天气预报员们将面临着每年最重要的一项任务：预测樱花开放的准确日期。

Japan's Sakura or cherry blossom season is feverishly anticipated by locals and visitors alike. Many tourists plan their entire trips around the blooms, and Japanese flock to parks in their millions to enjoy the seasonal spectacle.

当地人和游客都非常期待日本的樱花季。很多游客按照樱花季的时间规划整个行程，还有数百万日本人会在樱花季涌入公园饱览盛景。

"People pay more attention to the cherry blossom season than any other flower in Japan," Ryo Dojo, an official of the statistics unit at the Japan Meteorological Agency, told AFP.

日本气象厅统计部门官员道焦亮告诉法新社记者说：“在日本，人们对樱花的关注远多于其他花。”

The most basic element of predicting when the delicate pink and white petals will begin to unfurl is a large data set of temperatures.

要预测娇美的粉白色樱花何时盛开，最基本的是要基于大规模的气温数据集合。

unfurl [ʌn'fɜːl]：vt.展开；使…临风招展

 That's because the flowers will come earlier if temperatures rise quickly in spring.

因为如果气温在春季快速上升，樱花就会提早盛开。

Conversely, if temperatures in the autumn and winter period are higher than usual, the blooms can end up being delayed.

相反，如果此前的秋冬两季气温比平时高，樱花的开放时间会推迟。

Extreme weather can affect the trees too, with unusual patterns in 2018 prompting some blossoms to appear in October, well before the usual season.

极端天气也会影响樱树。2018年不寻常的气候类型导致一些樱花在10月开放，比平时提早太多。

In general, blooms begin as early as March in southern Kyushu and appear as late as May in northernmost Hokkaido.

一般来讲，日本南部九州的樱花早在三月就开放了，而在最北部的北海道，樱花要到五月才开放。

In a bid to improve its forecasts, some outfits have started crowdsourcing data, including Weathernews, a firm in Chiba near Tokyo.

为提高预测准确性，一些机构开始通过众包的方式收集数据，比如，东京附近千叶市的天气新闻公司。

It relies on photos of buds sent in regularly by 10,000 citizens across the country who are registered on the company's website and app.

这家公司的数据来源于1万名日本各地的市民定期发送的樱花花蕾照片。这些市民都在该公司的网站和应用程序上进行了注册。

"Cherry blossom forecasting is impossible for us without this system," a spokeswoman said.

公司一位女发言人说：“如果没有这个系统，我们就无法预测樱花盛开的时间。”

 200万份报告

The company launched what they call the "Sakura project" in 2004, signing up members who choose their own cherry tree and send pictures of its buds to the firm at regular intervals.

这家公司在2004年推出了“樱花项目”，与民众签约。民众选择所要观测的樱花树，并定期将花蕾照片发送给公司。

Just observing the bud can give surprisingly accurate information about how far the flower is from full bloom.

只需观察花蕾，就能给出樱花盛开时间的准确信息，着实出人意料。

A sakura bud still a month from blossoming will be small and firm, but after 10 days, the tip turns slightly yellow-green, and then a darker green part emerges.

还有一个月才开花的樱花花蕾小而紧实，但在10天之后，花蕾的顶部有些许变为黄绿色，之后会呈现出深绿色。

When the tip of the bud turns a faint pink, it's just a week until bloom-time.

花蕾的顶部变为淡粉色时，距离花开就只有一周了。

Thanks to the project, Weathernews has accumulated data from two million reports on cherry flower buds in the past 15 years, which it uses to increase the accuracy of its forecasting.

由于有了这个项目，天气新闻公司在过去15年间已经收集了樱花花蕾的200万份报告，公司以此提高了预测的准确性。

 It also incorporates weather data collected from its own observation devices across Japan－13,000 locations in total, 10 times more than the official weather agency has.

公司还整合了用自己的观测设备收集的天气数据，这些设备遍布日本1.3万处观测场所，比日本气象厅的观测场所多10倍。

Weathernews employees also call around 700 parks regularly to check the growth of cherry flower buds.

公司职员还会定期给700个公园打电话，核对樱花花蕾的生长情况。

The company and other forecasters also employ mathematical models and algorithms.

该公司和其他预测机构还使用了数字模型和算法。

Otenki Japan, a forecaster run by a subsidiary of precision-equipment manufacturer Shimadzu, even began using artificial intelligence to predict cherry blossoms in 2018.

精密仪器制造商日本岛津公司的子公司运营的预测机构Otenki Japan去年甚至开始使用人工智能预测花期。

subsidiary [səb'sɪdɪərɪ]：n.子公司

樱花季蕴藏大商机

The forecasts are not only for flower fans but reflect the fact that Sakura season is big business in Japan.

这些预测并不只针对赏花者，还说明赏樱在日本是个大生意。

Cherry blossoms symbolize the fragility of life in Japanese culture as full blooms only last about a week before the petals start falling off trees.

樱花盛开在日本文化中象征着生命的脆弱，因为花朵全部盛开的时间仅有一周左右，之后花瓣凋零落下。

And in that period and the preceding weeks, shops will pack their shelves with sakura-themed merchandise. Pink and white blossoms seem to decorate everything from beer cans to sakura-flavored chips and flower-themed candy.

在花期及之前数周，商店会囤满樱花主题商品。啤酒罐、樱花味薯条、樱花主题糖果……粉白色的樱花装点着各种商品。

Japan's Meteorological Agency stopped forecasting cherry blossoms in 2010, after more than five decades, saying other organizations were now making predictions with sufficient accuracy.

日本气象厅在2010年终止了其持续50多年的樱花花期预测工作，称其他机构目前的预测准确率已足够高。

The agency does however still declare the official start of cherry blossom season by monitoring 58 so-called barometer trees.

不过，日本气象厅还是会通过监测58棵“晴雨树”来正式宣布樱花季的开始。

The trees are at locations across the country, and the precise locations are considered a closely-guarded secret.

这些“晴雨树”遍布日本各地，但其准确地点秘而不宣。

From the beginning of March, inspectors visit the barometer trees once a day, with the trips increasing to twice daily as blossoming nears.

从3月初起，监测员每天去观察一次“晴雨树”。随着花期的临近，他们会改为每天去两次。